DaimlerChrysler has developed a treatment technology for diesel exhaust that allows it to meet the most stringent pollution restrictions. The technology, called Bluetec, will make its debut in Mercedes-Benz passenger cars and is slated to appear in other Chrysler Group diesels. A concept Grand Cherokee vehicle was shown at the 2006 North American International Auto Show in Detroit.
The system, now called Selective Catalytic Reduction or SCR, like systems under development by other carmakers, injects urea into the exhaust, where it reacts with oxides of nitrogen, helping eliminate troublesome NOx from the emissions. NOx is formed by the high combustion pressures in diesel engines and has been a key obstacle to making diesels as clean as today's gas engines.
Urea is a key component in liquid bodily waste, and as such isn't a popular topic of conversation for many. Chrysler's solution to this negative association is to dye it blue and give it a new name. The company is wrestling with the EPA over exactly how the system will work in the United States. Government regulators want the vehicle to shut down if it's allowed to run out of Bluetec fluid, a course of action that Chrysler, not surprisingly, finds unacceptable.
The company will provide refills at its dealers and has said that it's discussing the possibility of offering Bluetec fluid at Jiffy Lube centers to provide an even larger network of refill outlets. The system includes a catalytic converter and a particulate trap, which also can help scrub the exhaust of unburned hydrocarbons, carbon monoxide, and the black sooty particulates that make diesels look smoky when accelerating. Look for more SCR information as more vehicles use the technology.Dan Carney